Image reading apparatus capable of reading infrared and visible images

ABSTRACT

An image reading apparatus includes a light source with a first luminescent portion that outputs light with a first wavelength range and a second luminescent portion that outputs light with a second wavelength range, the wavelength ranges being different from each other; a light-receiving portion that receives light reflected from an original irradiated by the light source; a scanning portion that shifts a reading position of the original in a vertical scanning direction by changing a relative position between the original and the light-receiving portion; a switching portion that alternately turns on the first and second luminescent portions when the scanning portion shifts the reading position, wherein a vertical scanning resolution for a first data obtained when the first luminescent portion is turned on is independently set from a vertical scanning resolution for a second data obtained when the second luminescent portion is turned on.

This application is a Divisional of Copending U.S. patent applicationSer. No. 11/481,107, filed Jul. 6, 2006 now U.S. Pat. No. 7,432,492 andclaims the benefit of Japanese Patent Application No. 2006-058688, filedMar. 3, 2006, both of which are hereby incorporated in their entirety.

BACKGROUND OF THE INVENTION

The present invention relates to an image reading apparatus for readingimages on an original.

FIELD OF THE INVENTION

Reading devices such as a copy machine or a fax machine, or imagereading devices such as a scanner for automatically reading image datafrom an original to input the data into a computer are widely used. Inthis kind of image reading devices, the light is irradiated onto theoriginal from a light source, and the reflection light reflected fromthe original is received by an image sensor to read the image on theoriginal. Recently, an image reading device capable of reading colorimages as well as monochrome images has been widely popularized. Theimage reading device for reading color images usually adopts a lightsource capable of emitting red, green, and blue (RGB) lights and animage sensor in which multiple pixel lines corresponding to each colorare arranged in a vertical scanning direction. In addition, a colorfilter having a red, green, or blue color is provided in each pixel line(e.g., an on-chip filter).

However, the color filter installed in each pixel line often has aproperty of transmitting the light having a wavelength range other thanthat of a corresponding color, for example, a near infrared (IR) light.In this case, each pixel line is sensitive to the IR light as well asthe red, green, and blue lights. As a result, the data read by eachpixel line includes an IR light component as well as a desired colorlight component.

For this reason, a technique for inserting a reading filter for cuttingout unnecessary wavelength lights such as an infrared light in themiddle of an optical path for guiding the reflection light from theoriginal to each pixel line has been proposed.

In addition, recently, due to increasing concern about security orelectronization, a technique for forming an invisible image that cannotbe recognized by human eyes on a special original, for example using animage forming medium (such as ink or toner) that absorbs or reflects theIR rays, is being adopted in order to distinguish the special originalsuch as a note or a valuable paper from a typical original. In additionto the special original, for example, a technique for additionallyforming an invisible image containing code information (such as anidentification code) using the image forming medium on an original thathas visible confidential information has been considered.

Therefore, it is necessary to provide an image reading apparatus capableof reading an infrared image in addition to a visible image.

SUMMARY OF THE INVENTION

According to an aspect of the invention, there is provided an imagereading apparatus comprising: a light source that has a firstluminescent portion for outputting a light with a first wavelength rangeand a second luminescent portion for outputting a light with a secondwavelength range, the second wavelength range being different from thefirst wavelength range; a light-receiving portion that receives areflection light reflected from an original irradiated by the lightsource; a scanning portion that shifts a reading position of theoriginal read by the light-receiving portion in a vertical scanningdirection, by changing a relative position between the original and thelight-receiving portion; a switching portion that alternately turns onthe first and second luminescent portions when the scanning portionshifts the reading position, wherein a vertical scanning resolution fora first data obtained from the light-receiving portion when theswitching portion turns on the first luminescent portion isindependently set from a vertical scanning resolution for a second dataobtained from the light-receiving portion when the switching portionturns on the second luminescent portion.

BRIEF DESCRIPTION OF DRAWINGS

Exemplary embodiments of the present invention will be described indetail based on the following figures, wherein:

FIG. 1 is a diagram illustrating an exemplary construction of an imagereading apparatus according an exemplary embodiment of the presentinvention;

FIG. 2 is a diagram illustrating an exemplary construction of an LEDlight source;

FIG. 3 is a diagram illustrating a schematic construction of a CCD imagesensor;

FIGS. 4A and 4B are diagrams illustrating wavelength-luminescencecharacteristics of a white LED and an infrared LED, andwavelength-transmittance characteristic of a color filter provided ineach of red, green, and blue pixel lines, respectively;

FIG. 5 is a block diagram illustrating a control/image-processing unit;

FIG. 6 is a block diagram illustrating an exemplary construction of apre-processing portion;

FIG. 7 is a block diagram illustrating an exemplary construction of aninfrared post-processing portion;

FIG. 8 is a block diagram illustrating an exemplary construction of avisible post-processing portion;

FIGS. 9A, 9B, and 9C are diagrams for describing a two-dimensional codeimage included in an invisible image;

FIG. 10 is a flowchart for describing operations in an original-movablereading mode;

FIG. 11 is a diagram for describing the number of read lines required toread an image for one page of an original;

FIG. 12 is a timing chart illustrating a relationship between turning-onof the LED light source and an output from the CCD image sensor in afirst reading mode;

FIG. 13 is a timing chart illustrating relationships among a linesynchronization signal, an LED on/off switching signal, turning-on/offof a white LED and an infrared LED, a CCD capture signal, and first,second, and third data in a first reading mode;

FIG. 14 is a timing chart for describing operations of aninfrared/visible separator in a first reading mode;

FIG. 15 is a timing chart for describing operations of a rearrangingportion in a first reading mode;

FIG. 16 is a flowchart illustrating a process flow performed in anidentification information analyzing portion in a first reading mode;

FIGS. 17A, 17B, and 17C are timing charts for describing operations of adelay processing portion, a data supplementing portion, and an imageprocessing portion in a first reading mode;

FIG. 18 is a timing chart illustrating relationships among a linesynchronization signal, an LED on/off switching signal, turning-on/offof a white LED and an infrared LED, a CCD capture signal, and first,second, and third data in a second reading mode;

FIG. 19 is a timing chart for describing operations of aninfrared/visible separator in a second reading mode;

FIGS. 20A, 20B, and 20C are timing charts for describing operations of adelay processing portion, a data supplementing portion, and an imageprocessing portion in a second reading mode;

FIGS. 21A, 21B, 21C, and 21D are diagrams illustrating blue, green, andred color and infrared data output respectively in a first reading mode;

FIGS. 22A, 22B, and 22C are diagrams illustrating blue, green, and redcolor data output respectively in a second reading mode;

FIG. 23 is a diagram illustrating an exemplary construction of a VCLKgenerator according to a second exemplary embodiment of the presentinvention;

FIG. 24 is a timing chart illustrating relationships among a linesynchronization signal, an LED on/off switching signal, turning-on/offof a white LED and an infrared LED, a CCD capture signal, and first,second, and third data in a first reading mode;

FIG. 25 is a timing chart for describing operations of aninfrared/visible separator in a first reading mode; and

FIG. 26 is a timing chart for describing operations of a rearrangingportion in a first reading mode.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, a best mode for implementing the present invention(hereinafter, referred to as an exemplary embodiment) will be describedwith reference to the accompanying drawings.

First Exemplary Embodiment

FIG. 1 is a diagram illustrating an exemplary image reading apparatusaccording to a first exemplary embodiment of the present invention. Thisimage reading apparatus is designed to allow an image on a movableoriginal as well as an image on a fixed original to be read. Inaddition, the image reading apparatus includes an original conveyer 10for sequentially conveying the originals from multiple originals thathave been loaded and a reader 50 for reading an image through ascanning.

The original conveyer 10 comprises an original tray 11 for loadingmultiple originals and a discharge tray 12 provided under the originaltray 11 to receive the originals that have been read. The originalconveyer 10 has a nudger roller 13 for pulling out the original from theoriginal tray 11 and delivering it. In addition, a handling mechanism 14for handling each piece of papers using a feed roller and a retardroller is provided in a downstream side from the nudger roller 13 alongthe original conveyance direction. In a first conveyance path 31 forconveying the original, a pre-resist roller 15, a resist roller 16, aplaten roller 17, and an out roller 18 are provided in this order froman upstream side along an original conveyance direction. The pre-resistroller 15 conveys each processed original towards the rollers disposedin a downstream side and performs a loop formation of the original. Theresist roller 16 halts its rotation once and restarts to rotate insynchronization with the timing to supply the original while performinga registration adjustment for the original reading portion, which willbe described below. The platen roller 17 assists the conveyance of theoriginal which is being read by the reader 50. The out roller 18 conveysthe original that has been read by the reader 50 further downstream.

In addition, a second conveyance path 32 for guiding the original to thedischarge tray 12 is provided in a downstream side from the out roller18 along the original conveyance direction. The second conveyance path32 is provided with a discharge roller 19.

Furthermore, in this image reading apparatus, a third conveyance path 33is provided between an outlet of the out roller 18 and an inlet of thepre-resist roller 15. This allows the images formed on both sides of theoriginal to be read in one process. Also, the discharge roller 19 has afunction of making a reverse turn and conveying the original to thethird conveyance path 33.

Still furthermore, in this image reading apparatus, a fourth conveyancepath 34 is provided to make a reverse turn again and discharge theoriginal to the discharge tray 12 when a double-side reading isperformed. The fourth conveyance path 34 is disposed in an upper side ofthe second conveyance path 32. Also, the aforementioned discharge roller19 has a function of making a reverse turn and conveying the original tothe fourth conveyance path 34.

On the other hand, the reader 50 supports the original conveyer 10 toallow it to be opened/closed and also supports the original conveyer 10by using its device frame 51. The reader 50 also reads the images on theoriginal conveyed by the original conveyer 10. The reader 50 includes adevice frame 51 for forming a casing, a first platen glass 52A fordisposing the original to be read in a halted condition, and a secondplaten glass 52B having an optical opening for reading the originalconveyed by the original conveyer 10.

In addition, the reader 50 includes a full-rate carriage 53 that eitherstops under the second platen glass 52B or moves along the entiresurface of the first platen glass 52A to scan the image, and a half-ratecarriage 54 for supplying the light obtained from the full-rate carriage53 to an imaging unit. The full-rate carriage 53 includes an LED lightsource 55 for irradiating the original and a first mirror 57A forreceiving the reflection light from the original. In addition, thehalf-rate carriage 54 includes second and third mirrors 57B and 57C forproviding the light obtained from the first mirror 57A to the imagingunit. Furthermore, the reader 50 includes an imaging lens 58 and a CCD(charge coupled device) image sensor 59. The imaging lens 58 opticallyreduces the optical image obtained from the third mirror 57C. The CCDimage sensor 59 opto-electrically converts the optical image formedusing the imaging lens 58. In other words, the reader 50 forms an imageon the CCD image sensor 59 by using a form of reduction optics.

60 performs a predetermined processing for the original image data inputfrom the CCD In addition, a white reference board 56 extended along ahorizontal scanning direction is provided under a member providedbetween the first and second platen glasses 52A and 52B.

The reader 50 further includes a controller/image processor 60. Thecontroller/image processor image sensor 59. In addition, thecontroller/image processor 60 controls operations of each portion in aread operation of the entire image reading apparatus including theoriginal conveyer 10 and the reader 50.

Now, a fundamental read operation of the original using this imagereading apparatus will be described with reference to FIG. 1. Asdescribed above, the image reading apparatus can perform a readoperation for the original fixed on the first platen glass 52A (i.e., inan original-fixed reading mode) as well as a read operation for theoriginal conveyed by the original conveyer 10 (i.e., in anoriginal-movable reading mode).

First of all, an original-fixed reading mode will be described.

When an image of the original fixed on the first platen glass 52A isread, the full-rate carriage 53 and the half-rate carriage 54 areshifted along a scanning direction (an arrow direction in the drawing)in a ratio of 2:1. In this case, the light from the LED light source 55of the full-rate carriage 53 is irradiated onto a target surface of theoriginal. Then, the reflection light from the original is reflected onthe first, second, and third mirrors 57A, 57B, and 57C in this order soas to be guided to the imaging lens 58. The light guided to the imaginglens 58 forms an image on a light-receiving surface of the CCD imagesensor 59. As will be described below, the CCD image sensor 59 is aone-dimensional sensor, and simultaneously processes one line of animage. Then, the full-rate and half-rate carriages 53 and 54 are movedalong this line (i.e., along a vertical scanning direction) to read thenext line of the original. This operation is repetitively performed forthe entire surface of the original to complete a read operation for onepage of the original. In an original-fixed reading mode, the full-rateand half-rate carriages 53 and 54 function as a scanning portion or amoving portion.

Subsequently, an original-movable reading mode will be described.

When an image of the original conveyed by the original conveyer 10 is tobe read, the conveyed original passes through an upper side of thesecond platen glass 52B. In this case, the full-rate and half-ratecarriages 53 and 54 are arranged in a position shown as a solid line inFIG. 1 in a stop condition. Then, the reflection light corresponding toa first line of the original that has passed through the platen roller17 of the original conveyer 10 is guided to the imaging lens 58 via thefirst, second, and third mirrors 57A, 57B, and 57C to form an image, andthe formed image is read by the CCD image sensor 59. The CCD imagesensor 59 simultaneously processes one horizontal scanning line, andthen, the next horizontal scanning line of the original conveyed by theoriginal conveyer 10 is read. In addition, a read operation for one pageof the original along a vertical scanning direction is completed when abottom end of the original passes through a reading position of thesecond platen glass 52B after a top end of the original reaches areading position of the second platen glass 52B. In the original-movablereading mode, the original conveyer 10 functions as a scanning portionor a moving portion.

When images formed on both sides of the original are read, a drivingdirection of the discharge roller 19 is reversed just before a bottomend of the original that has been read for one surface passes throughthe discharge roller 19 provided in the second conveyance path 32. Inthis case, the original is guided to the third conveyance path 33 byswitching a direction of a gate (not shown in the drawing). It should benoted that the bottom end of the original is changed to the top end atthis time. In addition, after front and rear surfaces of the originalare turned over, the original passes through an upper surface of thesecond platen glass 52B, so that the rear surface of the original isread similarly to the aforementioned process for the front surface.Subsequently, a driving direction of the discharge roller 19 is reversedagain just before the bottom end of the original that has been read forthe rear surface passes through the discharge roller 19 provided in thesecond conveyance path 32. In this case, the original is guided to thefourth conveyance path 34 by switching a direction of a gate (not shownin the drawings). It should be noted that, unlike the original that hasbeen disposed initially on the original tray 11, the front and rearsurfaces are turned over, while its top and bottom ends are reversedagain when the original is discharged to the discharge tray 12. As aresult, multiple originals can be filed up in the same order betweenwhen they have been stored in the original tray 11 and when they aredischarged to the discharge tray 12.

Now, each portion of the image reading apparatus will be described inmore detail.

FIG. 2 is a diagram illustrating a construction of an LED light source55 as an example of a light source provided in the reader 50. The LEDlight source 55 irradiates the original from both sides of the firstmirror 57A as shown in FIG. 1. The LED light source 55 includes arectangular base portion 91 having an opening in its center, multiplewhite LEDs 92, and multiple infrared LEDs 93. The white LEDs 92 and theinfrared LEDs 93 are alternately arranged along a longitudinaldirection, i.e., a horizontal scanning direction of the original. Aswill be described below, the white LEDs 92 emit a white light containingred (R), green (G), and blue (B) colors. In addition, the infrared LEDs93 emit an infrared light containing IR rays.

FIG. 3 is a diagram illustrating a schematic construction of a CCD imagesensor 59 as a light-receiving portion provided in the reader 50. TheCCD image sensor 59 includes a rectangular sensor board 59 a and threepixel lines (i.e., multiple pixel lines) 59R, 59G, and 59B arranged onthe sensor board 59 a. Hereinafter, the three pixel lines 59R, 59G, and59B are referred to as a red pixel line 59R, a green pixel line 59G, anda blue pixel line 59B, respectively. The red, green, and blue pixellines 59R, 59G, and 59B are arranged in parallel along a directionorthogonal to the original conveyance direction. The red, green, andblue pixel lines 59R, 59G, and 59B may be constructed, for example, byarranging a number k of photodiodes PD having an area of 10 μm×10 μm ina straight line, respectively. It should be noted that, according to thepresent exemplary embodiment, the reading resolutions in a horizontalscanning direction (hereinafter, referred to as a horizontal scanningresolution) for the red, green, and blue pixel lines 59R, 59G, and 59Bare set to, for example, 600 spi (samples per inch). In addition, aninterval between the blue and green pixel lines 59B and 59G and aninterval between the green pixel line 59G and the red pixel line 59R areset to 2 lines in a vertical scanning direction, respectively.

The red, green, and blue pixel lines 59R, 59G, and 59B are provided witha color filter for transmitting other wavelength components,respectively, so that each of the red, green, and blue pixel lines 59R,59G, and 59B functions as a color sensor. Additionally, each colorfilter provided in each of the red, green, and blue pixel lines 59R,59G, and 59B is designed to transmit an IR light having a predeterminedwavelength range in addition to a respective visible light. For thisreason, the red, green, and blue pixel lines 59R, 59G, and 59B alsofunction as an IR pixel line, respectively.

FIG. 4A is a diagram illustrating wavelength-luminescencecharacteristics of a white LED 92 as a first luminescent portion and aninfrared LED 93 as a second luminescent portion. The white LED 92includes a bluish-purple light-emitting diode having a blue wavelengthrange (e.g., 405 nm) and red, green, and blue fluorescent materials, andemits a light across a continuous wavelength range from a blue range (inthe vicinity of 400 nm) through a green range (in the vicinity of 550nm) to a red range (in the vicinity of 800 nm). However, as shown inFIG. 4A, the white LED 92 emits almost no light within a near-infraredrange (800-1,000 nm). On the other hand, the IR LED 93 includes aninfrared light-emitting diode having an infrared wavelength range (inthe vicinity of 850 nm). However, as shown in FIG. 4A, the IR LED 93emits almost no light within a visible wavelength range (400-800 nm).Therefore, the white LED 92 emits a light having a visible range as afirst wavelength range, and the IR LED 93 emits a light having aninfrared range as a second wavelength range.

It should be noted that, although a white LED 92 having theaforementioned construction is used in the present exemplary embodiment,the present invention is not limited thereto. FIG. 4A also shows aluminescent characteristic of a white LED 92 manufactured by combiningthe blue, green, and red LEDs. That is, a white light may be produced bycombining the blue, green, and red LEDs. In this case, there should beno luminescent spectrum within a near-infrared range, or if any, itsintensity should be negligible. When a white LED 92 has a luminescentspectrum in the vicinity of the near-infrared range and reverselyworsens color image quality, it is necessary to provide a separatefilter for cutting off infrared components near the white LED 92. Inthis case, the infrared cut-off filter should not be disposed in theoptical path of the IR LED 93.

FIG. 4B shows a wavelength-transmittance characteristic of a colorfilter provided in the aforementioned red, green, and blue pixel lines59R, 59G, and 59B. The color filter provided in the blue pixel line 59Btransmits the light having a blue wavelength range but cuts off almostof the light having a green or red wavelength range. Similarly, thecolor filter provided in the green pixel line 59G transmits the lighthaving a green wavelength range but cuts off almost of the light havinga blue or red wavelength range. Similarly, the color filter provided inthe red pixel line 59R transmits the light having a red wavelength rangebut cuts off almost of the light having a blue or green wavelengthrange. However, the color filters provided in the red, green, and bluepixel lines 59R, 59G, and 59B, respectively, have an appropriatetransmittance for the light having a near-infrared wavelength range (inthe vicinity of 850 nm).

FIG. 5 is a block diagram illustrating a controller/image processor 60of FIG. 1. The controller/image processor 60 includes a signalprocessing portion 70 and a control portion 80. The signal processingportion 70 processes the image data input from the CCD image sensor 59(more specifically, from the blue, green, and red pixel lines 59B, 59G,and 59R). In addition, the controller 80 controls operations of theoriginal conveyer 10 and the reader 50.

The signal processing portion 70 includes a pre-processing portion 100,an infrared post-processing portion 200, a visible post-processingportion 300, and a data combining portion 400.

The pre-processing portion 100 converts each of the (analog) image datainput from the blue, green, and red pixel lines 59B, 59G, and 59R of theCCD image sensor 59 into digital data. In addition, the pre-processingportion 100 separates each of the converted digital image data intoimage data for an invisible image and image data for a visible image aswill be described below and outputs them.

The infrared post-processing portion 200 functioning as a secondacquisition portion, an identification information acquisition portion,or a second processing portion analyzes the input image data for theinvisible image to extract and output the identification informationincluded in the invisible image.

The visible post-processing portion 300 functioning as a firstacquisition portion, an image information acquisition portion, or afirst processing portion performs a predetermined image process for theinput image data for the visible image and outputs the result as imageinformation.

The data combining portion 400 combines the identification informationinput from the infrared post-processing portion 200 and the image dataoutput from the visible post-processing portion 300 and outputs theresult to a device (e.g., a printer or a personal computer (PC))provided in a subsequent stage.

Meanwhile, the controller 80 includes a reading controller 81, a CCDdriver 82, an LED driver 83, a scan driver 84, and a conveyer driver 85.

The reading controller 81 performs various kinds of controls for readingthe original as well as controls for the entire image reading apparatusincluding the original conveyer 10 and the reader 50 shown in FIG. 1.

The CCD driver 82 controls an operation of receiving the image datathrough the CCD image sensor 59 (including the blue, green, and redpixel lines 59B, 59G, and 59R: refer to FIG. 3).

The LED driver 83 functioning as a switching portion outputs the LEDon/off switching signal to control turning-on/off of the white LED 92and the infrared LED 93 of the LED light-source 55 in synchronizationwith the reading timing for the original. The scan driver 84 turnson/off a motor in the reader 50 to control a scan operation of thefull-rate and half-rate carriages 53 and 54.

The conveyer driver 85 controls tuning-on/off of a motor, variousrollers, clutches, and a gate in the original conveyer 10.

Control signals are output from such various drivers to the originalconveyer 10 and the reader 50, so that they can be controlled based onsuch control signals. The reading controller 81 presets a reading modebased on, for example, a control signal from a host system, a sensoroutput detected in an automatic selection reading function, selection ofa user, and the like to control the original conveyer 10 and the reader50. This reading mode may include an original-fixed reading mode forreading the original fixed on the first platen glass 52A and anoriginal-movable reading mode for reading the original conveyed throughthe second platen glass 52B. In addition, the original-movable readingmode may include a single-side mode for reading an image on only asingle side of the original, a double-side mode for reading images onboth sides of the original, and the like.

In addition, the controller 80 additionally includes a video clock(VCLK) generator 86, a line synchronization signal generator 87, and apage synchronization signal generator 88.

The VCLK generator 86 generates a video clock serving as a referencesignal for the image read operation. The VCLK clock is output to theline synchronization signal generator 87, the page synchronizationsignal generator 88, and the reading controller 81, respectively. Thisvideo clock period is set to a sufficiently low value in comparison witha line period, which will be described below.

The line synchronization generator 87 generates a line synchronizationsignal. The line synchronization signal is instantaneously asserted inevery line period when the CCD image sensor 59 obtains image data forone line in a horizontal scanning direction of the original. In thisexemplary embodiment, it is assumed that the line synchronization signalis asserted every time a count value for the video clocks input from theVCLK generator 86 is coincident with a predetermined value.

The page synchronization signal generator 88 generates a pagesynchronization signal. The page synchronization signal is asserted onlyfor a reading period corresponding to one sheet of the original to beread. In the present exemplary embodiment, it is assumed that the pagesynchronization signal starts to be asserted when the top end of theoriginal reaches a reading position for the CCD image sensor 59. Thepage synchronization signal is negated when a count value for the linesynchronization signal counted from this time point is coincident with apredetermined setup value.

FIG. 6 is a block diagram illustrating an exemplary construction of theaforementioned pre-processing portion 100. The pre-processing portion100 includes an analog processing portion 110, an A/D converter 120, andan infrared/visible separator 130. The analog processing portion 110independently receives first, second, and third data Br, Gr, and Rrinput from the blue, red, and green pixel lines 59B, 59G, and 59R,respectively, of the CCD image sensor 59. In addition, the first,second, and third data Br, Gr, and Rr input from the CCD image sensor 59are analog data.

The analog processing portion 110 executes analog correction such as again and offset adjustment for the first, second, and third data Br, Gr,and Rr.

The A/D converter 120 converts the first, second, and third data Br, Gr,and Rr into digital data after the analog correction.

The infrared/visible separator 130 functioning as a separator separatesthe first, second, and third data Br, Gr, and Rr into the data obtainedwhen the white LED 92 is turned on and the data obtained when theinfrared LED 93 is turned on, and outputs them (refer to FIG. 2). An LEDon/off switching signal is input from the LED driver 83 (refer to FIG.5) to the infrared/visible separator 130, and the infrared/visibleseparator 130 performs an operation of separating and outputting theinfrared and visible lights based on the LED turning-on/off signal.Specifically, the infrared/visible separator 130 separates the firstdata Br into the first infrared data IR1(B) and the first visible dataVIS1(B). Similarly, the infrared/visible separator 130 separates thesecond data Gr into the second infrared data IR2(G) and the secondvisible data VIS2(G). Similarly, the infrared/visible separator 130separates the third data Rr into the third infrared data IR3(R) and thethird visible data VIS3(R). Then, the first, second, and third infrareddata IR1(B), IR2(G), and IR3(R) are output to the infraredpost-processing portion 200 as second data or multiple received data. Onthe other hand, the first, second, and third visible data VIS1(B),VIS2(G), and VIS3(R) are output to the visible post-processing portion300 as first data.

The acquisition completion signal output is input from theidentification information analyzer 250 (refer to FIG. 7, as will bedescribed below) provided in the infrared post-processing portion 200 tothe infrared/visible separator 130 when acquisition of theidentification information is completed. In response to the acquisitioncompletion signal, the infrared/visible separator 130 stops separatingthe first, second, and third data Br, Gr, and Rr, and outputs the first,second, and third data Br, Gr, and Rr as the first, second, and thirdvisible data VIS1(B), VIS2(G), and VIS3(R), respectively, without anychange.

FIG. 7 is a block diagram illustrating an exemplary construction of theaforementioned infrared post-processing portion 200. The infraredpost-processing portion 200 includes an infrared shading dataacquisition portion 210, an infrared shading data storing portion 220,an infrared shading correction portion 230, a rearranging portion 240,and an identification information analyzing portion 250. In addition,the first, second, and third infrared data IR1(B), IR2(G), and IR3(R)are independently input to the infrared post-processing portion 200 asdescribed above.

The infrared shading data acquisition portion 210 acquires infraredshading data SHD(IR) that will be used in the shading correction for theinfrared image data of the original. The infrared shading data SHD(IR)are set for the blue, green, and red pixel lines 59B, 59G, and 59R,respectively.

The infrared shading data storing portion 220 stores the infraredshading data SHD(IR) acquired from the infrared shading data acquisitionportion 210.

The infrared shading correction portion 230 functioning as the secondshading correction portion performs infrared shading correction for theinput first, second, and third infrared data IR1(B), IR2(G), and IR3(R)by using each infrared shading data SHD(IR) read from the infraredshading data storing portion 220.

In the infrared shading correction, the input first, second, and thirdinfrared data IR1(B), IR2(G), and IR3(R) are corrected based onvariations of sensitivities of photodiodes PDs in each of the blue,green, and green pixel lines 59B, 59G, and 59R or the light intensitydistribution characteristics in the LED light source 55 (in this case,the infrared LED 93).

The rearranging portion 240 rearranges the first, second, and thirdinfrared data IR1(B), IR2(G), and IR3(R) input after the infraredshading correction is completed and outputs the infrared data IR assecond image data (i.e. infrared image data), third image data, or asingle piece of received data.

The identification information analyzing portion 250 analyzes theidentification information from the code image included in the inputinfrared data IR and outputs the obtained identification information tothe data combining portion 400 (FIG. 5). The identification informationanalyzing portion 250 outputs an acquisition completion signal,representing that the identification information has been acquired, tothe infrared/visible separator 130 (FIG. 6) when the analysis of theidentification information is completed.

FIG. 8 is a block diagram illustrating an exemplary construction of theaforementioned visible post-processing portion 300. The visiblepost-processing portion 300 includes a visible shading data acquisitionportion 310, a visible shading data memory 320, and a visible shadingdata correction portion 330. Also, the visible post-processing portion300 additionally includes a delay processing portion 340, a datasupplementing portion 350, and an image processing portion 360.

The visible shading data acquisition portion 310 acquires visibleshading data SHD(VIS) to be used in the shading correction of thevisible image data of the original.

In addition, the visible shading data SHD(VIS) are set for each of theblue, green, and red pixel lines 59B, 59G, and 59R, similarly to theaforementioned infrared shading data SHD(IR).

The visible shading data memory 320 stores the visible shading dataSHD(VIS) acquired from the visible shading data acquisition portion 310.

The visible shading correction portion 330 functioning as a firstshading correction portion performs the shading correction for thefirst, second, and third visible data VIS1(B), VIS2(G), and VIS3(R) byusing each shading data SHD(VIS) read from the visible shading datamemory 320.

In the visible shading correction, the input first, second, and thirdvisible data VIS1(B), VIS2(G), and VIS3(R) are corrected based onvariations of sensitivities of photodiodes PD in each of the blue,green, and red pixel lines 59B, 59G, and 59R or the light intensitydistribution characteristics in the LED light source 55 (in this case,the white LED 92).

The delay processing portion 340 corrects the gap generated by differentinstallation locations among the blue, green, and red pixel lines 59B,59G, and 59R (of FIG. 3). In other words, as shown in FIG. 3, there isan interval of 2 lines between the green pixel line 59G and the redpixel line 59R in a vertical scanning direction, and there is also aninterval of 2 lines between the blue pixel line 59B and the green pixelline 59G in a vertical scanning direction. For this reason, when theoriginal is read by the image reading apparatus according to the presentexemplary embodiment, a particular area (in a horizontal scanningdirection) in the original is firstly read by the blue pixel line 59B,read by the green pixel line 59G, and then, read by the red pixel line59R. From a different viewpoint, each of the blue, green, and red pixellines 59B, 59G, and 59R reads different areas of an image at the sametiming since there is an interval of 2 lines in a vertical scanningdirection between each line. Therefore, the delay processing portion 340uses the third visible data VIS3(R) lastly read by the red pixel line59R as a delay reference, and delays the second visible data VIS2(G)read by the green pixel line 59G by 2 lines in a vertical scanningdirection with respect to the third visible data VIS3(R) and also thefirst visible data VIS1(B) read by the blue pixel line 59B by 4 lines ina vertical scanning direction with respect to the third visible dataVIS3(R) (i.e., by 2 lines in a vertical scanning direction with respectto the second visible data VIS2(G)). As a result, the first, second, andthird visible data VIS1(B), VIS2(G), and VIS3(R) obtained by reading thesame area (corresponding to the same horizontal scanning line) of theoriginal are synchronized and output from the delay processing portion340.

The data supplementing portion 350 supplements the first, second, andthird visible data VIS1(B), VIS2(G), and VIS3(R) to fill the dataomitted by the separation in the infrared/visible separator 130 (referto FIG. 6). In addition, the omitted data corresponds to the data outputwhen the infrared LED 93 (refer to FIG. 2) is turned on, i.e., includingthe first, second, and third infrared data IR1(B), IR2(G), and IR3(R).

Furthermore, an acquisition completion signal is input to the datasupplementing portion 350 from the identification information analyzingportion 250 (refer to FIG. 7) provided in the infrared post-processingportion 200. In response to the acquisition completion signal, the datasupplementing portion 350 stops supplementing the aforementioned data,and outputs the first, second, and third visible data VIS1(B), VIS2(G),and VIS3(R) without any change.

The image processing portion 360 performs various kinds of imageprocessing for the first, second, and third visible data VIS1(B),VIS2(G), and VIS3(R), and outputs the blue, green, and red image data B,G, and R as image information or first image data (i.e., visible imagedata) to the data combining portion 400 (refer to FIG. 5). Processesperformed in the image processing portion 360 may include, for example,Y/gray balance adjustment, color space conversion,enlargement/reduction, filtering, contrast adjustment, backgroundelimination, and the like.

Now, an image of the original to be read by this image reading apparatuswill be described in detail. The image reading apparatus may read anoriginal having a visible image and an invisible image formed from acode image including the aforementioned identification information aswell as an original having only a typical visible image formed fromcommon colors such as yellow, magenta, cyan, and black. It should benoted that classification between “visible” and “invisible” does notdepend on whether or not they can be recognized by human eyes. In otherwords, classification between “visible” and “invisible” depends onwhether or not the image formed on a paper medium can be recognizedbased on chromogenicity caused by light absorption of a particularwavelength in a visible wavelength range.

FIGS. 9A, 9B, and 9C are diagrams for describing a two-dimensional codeimage included in the invisible image. FIG. 9A illustrates a latticestructure for schematically showing a unit of a two-dimensional codeimage formed from an invisible image. In addition, FIG. 9B is a diagramillustrating a unit of a two-dimensional code image, and FIG. 9C is adiagram for describing a slanted-line pattern including slashes “/” andbackslashes “\”.

The two-dimensional images shown in FIGS. 9A, 9B, and 9C are formed froman invisible image capable of safely performing a machine read operationby infrared light irradiation and a decoding process for a long timeperiod, and also capable of recording information with a high density.In addition, it is preferable that the invisible image can be providedon an arbitrary area regardless of the area where the visible image isformed on a surface of a medium for outputting an image. In the presentexemplary embodiment, the invisible image is formed on the entiresurface of a medium (i.e., a paper) according to the size of a medium tobe printed. In addition, it is more preferable to provide an invisibleimage capable of being recognized by human eyes with a difference inglossiness. However, the “entire surface” should not be considered toinclude all of four corners of a paper. In electro-photographic devicessuch as a laser printer, since there are many unprintable areas on edgesof a paper, it is unnecessary to print the invisible image on suchareas. Furthermore, it is assumed in the present embodiment that thetwo-dimensional code image is formed of a material having an absorptionpeak in the vicinity of a wavelength of 850 nm.

The two-dimensional code pattern shown in FIG. 9B includes an area forstoring a position code representing a coordinate position on a mediumand an area for storing an identification code for identifying anelectronic document or a printing medium. Also, the two-dimensional codepattern includes an area for storing a synchronization code. Inaddition, as shown in FIG. 9A, multiple two-dimensional code patternsare arranged in a lattice structure in which other kinds of positioninformation are stored on the entire surface of one page of a medium(i.e., a paper) according to the printing size of the medium.Specifically, as shown in FIG. 9B, multiple two-dimensional codepatterns are arranged on one surface of a medium, and each includes aposition code, an identification code, and a synchronization code. Inaddition, different kinds of position information are stored in each ofthe position code areas depending on where they are arranged. On theother hand, the same identification information is stored in multipleidentification code areas regardless of where they are arranged.

In FIG. 9B, the position code is disposed within a rectangular area of 6bits×6 bits. Each bit may be formed with multiple minute line bitmapshaving different rotation angles, and a bit value of 0 or 1 isrepresented by the slanted-line pattern (including a pattern of 0 or 1)as shown in FIG. 9C. More specifically, a bit value of 0 or 1 isrepresented by a slash “/” or a backslash “\” having a different slantedangle. The slanted-line pattern is constructed in a pixel size of 8×8with a resolution of 600 dpi (dot per inch). The backslash pattern(e.g., a pattern of 0) designates a bit value of 0, and the slashpattern (e.g., a pattern of 1) designates a bit value of 1. Therefore,one slanted-line pattern can be used to express one bit (0 or 1). Byusing the aforementioned minute line bitmap having two kinds of slantedangles, it is possible to provide a two-dimensional code pattern havinglittle noise on the visible image and capable of digitizing andembedding an amount of information in a high density.

In other words, position information including a total of 36 bits isstored in the position code area shown in FIG. 9B. Among 36 bits, 18bits may be used in an X-coordinates encoding, and the remaining 18 bitsmay be used in a Y-coordinate encoding. If each of 18 bits is used forencoding all positions, 2¹⁸(i.e., about 260,000) positions can beencoded. As shown in FIG. 9C, when each slanted-line pattern has a pixelsize of 8×8 (600 dpi), the size of one dot is 0.0423 mm in 600 dpi.Therefore, both horizontal and vertical lengths of the two-dimensionalcode (including a synchronization code) shown in FIG. 9( b) become about3 mm (=8 pixels×9 bits×0.0423 mm). When 260,000 positions are encodedwith an interval of 3 mm, a length of 786 m can be encoded. All of 18bits may be used in the encoding as described above, or a part of themmay include a redundancy check bit for error detection or errorcorrection when it is suspected that errors in detecting theslanted-line patterns can occur.

The identification code is arranged in a rectangular area of 2 bits×8bits or 6 bits×2 bits and may store identification information of atotal of 28 bits. When all of 28 bits are used for the identificationinformation, 2²⁸ pieces (about 270,000,000) of identificationinformation can be expressed. Similarly, a part of the identificationcode of 28 bits may include a redundancy check bit for error detectionor error correction.

In addition, although the slanted-line pattern has two elements havingan angle difference of 90° in the example shown in FIG. 9C, theslanted-line pattern may be constructed to have four elements if theangle difference is set to 45°. In this case, one slanted-line patterncan be used to express 2 bit information (0-3). That is, the number ofavailable bits can be increased by increasing the kinds of the anglesbetween elements of the slanted-line pattern.

In addition, although bits are encoded by using the slanted-line patternin the example shown in FIG. 9C, a selectable pattern is not limited tothe slanted-line pattern. For example, other encoding methods such as adot On/Off pattern or a deviated direction of a dot position withrespect to a reference position can be used.

Now, operation flows in the image reading apparatus will be described inmore detail by exemplifying the aforementioned original-movable readingmode. FIG. 10 is a flowchart for describing operations in the imagereading apparatus in an original-movable reading mode.

When a set of originals in the original tray 11 are detected by a sensor(step 101), the reading controller 81 determines the size of theoriginal based on the detection result of the sensor (step 102).

Then, the reading controller 81 outputs control signals to each driverin the controller 80 or each processing portion in the signal processingportion 70. Subsequently, gain and offset adjustment is executed (step103), and the visible shading data SHD(VIS) (step 104) and the infraredshading data SHD(IR) (step 105) are acquired.

Then, a read start instruction is received from user's input of a hostsystem or a user interface (step 106). Accordingly, the readingcontroller 81 outputs control signals to each driver in the controller80 or each processing portion in the signal processing portion 70 toread an image of the original in a first reading mode (step 107). Forexample, the first reading mode is to alternately read the visible andinvisible images on the original as will be described below. While theoriginal is read in the first reading mode, the code information in theinvisible image that has been read is analyzed in the identificationinformation analyzing portion 250 of the infrared post-processingportion 200, and the identification information is acquired from thecode information. Then, the reading controller 81 determines whether ornot the acquisition of the identification information in theidentification information analyzing portion 250 has been completed(step 108). Specifically, the reading controller 81 determines whetheror not the acquisition completion signal has been input from theidentification information analyzing portion 250. If it is determinedthat the acquisition of the identification information is not completed,the reading controller 81 determines whether or not a reading for onesheet of the original has been completed (step 109). If it is determinedthat the reading for one sheet of the original is not completed, theprocess returns to the step 107, and resumes the reading in the firstreading mode. Otherwise, if it is determined that the reading for onesheet of the original is completed, the process advances to the step112, which will be described below.

On the other hand, in the step 108, if it is determined that theacquisition of the identification information is completed, the readingcontroller 81 outputs control signals to each driver of the controller80 or each processing portion in the signal processing portion 70, andexecutes the reading of the original image in a second reading mode(step 110). The second reading mode is to read only visible images onthe original as will be described below. Then, the reading controller 81determines whether or not the reading for one sheet of the original hasbeen completed (step 111). If it is determined that the reading for onesheet of the original is not completed, the process returns to the step110 to resume the reading in the second reading mode. Otherwise, if itis determined that the reading for one sheet of the original iscompleted, the process advances to the step 112.

In the aforementioned step 109 or 111, if it is determined that thereading for one sheet of the original is completed, the readingcontroller 81 determines whether or not there is a next original to besubsequently read (step 112). If it is determined that there is a nextoriginal, the process returns to the step 107 to execute the sameprocesses for the next original. Otherwise, if it is determined thatthere is no next original, a set of processes are terminated.

Now, the steps 103-105 will be described in detail.

The reading controller 81 outputs a control signal to the scan driver 84in response to detecting a set of originals in the original tray 11 by asensor. In response to this control signal, the scan driver 84 shiftsthe full-rate carriage 53 to a position just under the white referenceboard 56 shown in FIG. 1, and shifts the half-rate carriage 54 to acorresponding position.

Then, the reading controller 81 outputs a control signal to the LEDdriver 83 in response to shifting the full-rate and half-rate carriages53 and 54 to predetermined positions. In response to this controlsignal, the LED driver 83 outputs an LED on/off switching signal forturning on only the white LED 92, and as a result, the white LED 92 isturned on. In addition, the reading controller 81 simultaneously outputsa control signal to the CCD driver 82 when the turning-on of the LED iscontrolled. In response to this control signal, the CCD driver 82executes the read operation of the CCD image sensor 59 (including theblue, green, and red pixel lines 59B, 59G, and 59R). In this case, theblue, green, and red pixel lines 59B, 59G, and 59R receive thereflection light from the white reference board 56 irradiated by thewhite LED 92. Then, each of the read data (the first data) from theblue, green, and red pixel lines 59B, 59G, and 59R is transmitted to theanalog processing portion 110 of the pre-processing portion 100, and anA/D conversion is performed. A coefficient 1 used in the D/A conversionin the subsequent stage is calculated so that the data having a highestreflection can be a predetermined target value, and stored in a memory(not shown in the drawing) provided in the analog processing portion110. Hereinbefore, calculation of a gain has been described.

Then, the reading controller 81 outputs a control signal to the LEDdriver 83. In response to this control signal, the LED driver 83 turnsoff the white LED 92. In this situation, both of the white LED 92 andthe infrared LED 93 are turned off. In addition, the reading controller81 outputs a control signal to the CCD driver 82. In response to thiscontrol signal, the CCD driver 82 executes a read operation in the CCDimage sensor 59 (including the blue, green, and red pixel lines 59B,59G, and 59R). Each read data (second data) from the blue, green, andred pixel lines 59B, 59G, and 59R is transmitted to the analogprocessing portion 110 of the pre-processing portion 100, and an A/Dconversion is performed. Then, a coefficient 2 used in a D/A conversionin the subsequent stage is calculated such that an average of the readdata can be a predetermined target value, and stored in a memory (notshown in the drawings) provided in the analog processing portion 110.

Through the aforementioned processes, the step 103 is completed. Inaddition, the reason for not using the infrared LED 93 for the gainadjustment in the step 103 is that it is preferable to design such thatthe CCD output generated when the white LED 92, which finally deals withmulti-value data, is higher than that generated when the infrared LED 93is turned on.

In response to completing the gain and offset adjustment, the readingcontroller 81 outputs a control signal to the LED driver 83, and turnson the white LED 92 again. Subsequently, the reading controller 81outputs a control signal to the CCD driver 82. In response to thiscontrol signal, the CCD driver 82 executes a read operation in the CCDimage sensor 59 (including the blue, green, and red pixel lines 59B,59G, and 59R) with the white LED 92 being turned on. In this case, theblue, green, and red pixel lines 59B, 59G, and 59R receive a reflectionlight (a visible light) from the white reference board 56 irradiated bythe white LED 92.

Each of the read data from the blue, green, and red pixel lines 59B,59G, and 59R is input to the visible shading data acquisition portion310 of the visible post-processing portion 300 after processes in thepre-processing portion 100 are performed. The visible shading dataacquisition portion 310 acquires corresponding visible shading dataSHD(VIS) from the read data obtained from the blue, green, and red pixellines 59B, 59G, and 59R, and the acquired visible shading data SHD(VIS)are stored in the visible shading data memory 320. Through theaforementioned processes, the step 104 is terminated

In response to completing the acquisition of the visible shading dataSHD(VIS), the reading controller 81 outputs a control signal to the LEDdriver 83. In response to this control signal, the LED driver 83 outputsan LED on/off switching signal for turning on only the infrared LED 93to the LED light source 55, and as a result, the infrared LED 93 isturned on. At the same time, the reading controller 81 outputs a controlsignal to the CCD driver 82. In response to this control signal, the CCDdriver 82 executes a read operation in the CCD image sensor (includingthe blue, green, and red pixel lines 59B, 59G, and 59R) with theinfrared LED 93 being turned on. In this case, the blue, green, and redpixel lines 59B, 59G, and 59R receive a reflection light (an infraredlight) from the white reference board 56 irradiated by the infrared LED93.

Each of the read data from the blue, green, and red pixel lines 59B,59G, and 59R is input to the infrared shading data acquisition portion210 of the infrared post-processing portion 200 after processes in thepre-processing portion 100 is executed. The infrared shading dataacquisition portion 210 acquires corresponding infrared shading dataSHD(IR) from each of the read data obtained from the blue, green, andred pixel lines 59B, 59G, and 59R, and stores the acquired infraredshading data SHD(IR) in the infrared shading data memory 220. Throughthe aforementioned processes, the step 105 is completed.

Now, the first reading mode in the step 107 and the second reading modein the step 110 will be described in detail. In addition, before thefirst and second reading modes are described, various conditions orsettings that should be set forth before the read operation for theoriginal is initiated will be described.

FIG. 11 is a diagram for describing the number X (where, X is an integernot less than 1) of the read lines required to read one page of theoriginal. In this image reading apparatus, one line of the image on theoriginal is read in a horizontal scanning direction FS by using the CCDimage sensor 59 (refer to FIG. 1) as described above. Then, the CCDimage sensor 59 and the original are relatively shifted with respect toeach other in a vertical scanning direction SS to read the next line ofthe image on the original in a horizontal scanning direction FS. Itshould be noted that in the original-fixed reading mode, the relativeposition between the CCD image sensor 59 and the original changes bymoving the full-rate and half-rate carriages 53 and 54. On the contrary,in the original-movable reading mode, the relative position between theCCD image sensor 59 and the original changes by moving the original.

In addition, the number X of the read lines is determined based on thelength of the original in a vertical scanning direction and a requiredreading resolution in a vertical scanning direction (hereinafter, avertical scanning resolution). For example, assuming that the originalhaving a size of A4SEF (Short Edge Feed) is read in a vertical scanningresolution of 600 spi, the required number X of read lines is about7,000.

FIG. 12 is a timing chart illustrating relationships among the pagesynchronization signal Psync output from the synchronization signalgenerator 88 shown in FIG. 5, the line synchronization signal Lsyncoutput from the line synchronization signal generator 87, and the CCDcapture signal CCD SH output from the CCD driver 82 through the readingcontroller 81.

The page synchronization signal generator 88 asserts the pagesynchronization signal Psync for only the reading period correspondingto one page for one sheet of the original to be read, as describedabove. In addition, a period after the page synchronization signal Psyncis asserted until when the next page synchronization signal Psync isasserted is called a page period TP.

In addition, the line synchronization signal generator 87 asserts theline synchronization signal Lsync for every period required to acquireimage data corresponding to one line on the original in a horizontalscanning direction, as describe above.

In addition, the CCD driver 82 asserts the CCD capture signal CCD SH insuch a way that the image data can be captured by the CCD image sensor59 in synchronization with the line synchronization signal Lsync, whilethe page synchronization signal Psync is asserted. In addition, thenumber of asserting the CCD capture signal while the pagesynchronization signal Psync is asserted is identical to theaforementioned number X of read lines.

Now, the first reading mode in the step 107 will be described withreference to FIGS. 13 to 17.

FIG. 13 is a timing chart illustrating relationships among the linesynchronization signal Lsync, the LED on/off switching signal,turning-on/off of the white and infrared LEDs 92 and 93, the CCD capturesignal CCD SH, and the first, second, and third data Br, Gr, and Rr inthe first reading mode. Herein, a period after the line synchronizationsignal Lsync is asserted until the next line synchronization signalLsync is asserted is called a line period TL.

When the first reading mode is initiated, the LED driver 83 outputs theLED on/off switching signal based on the line synchronization signalLsync input through the reading controller 81. Specifically, the LEDdriver 83 counts the number of assertions the line synchronizationsignal Lsync, and outputs an LED on/off switching signal to the LEDlight source 55, so that only the white LED 92 is turned on for 5 linescorresponding to the first to fifth counts, and only the infrared LED 93is turned on for the sixth line corresponding to the sixth count.

In response to the LED on/off switching signal, the LED light source 55repeatedly performs a turning-on/off operation in such a way that onlythe white LED 92 is turned on for 5 line periods TL corresponding to 5lines and only the infrared LED 93 is turned on for the next line periodTL corresponding to 1 line.

On the other hand, the CCD driver 82 outputs the CCD capture signal CCDSH synchronized with the line synchronization signal Lsync to the CCDimage sensor 59 (including the blue, green, and red pixel lines 59B,59G, and 59R). In response to the CCD capture signal CCD SH, the blue,green, and red pixel lines 59B, 59G, and 59R sequentially output theread data corresponding to one line in a horizontal scanning directionas the first, second, and third data Br, Gr, and Rr, respectively.

It should be noted that the blue, green, and red pixel lines 59B, 59G,and 59R are spaced with an interval of 2 lines in a vertical scanningdirection as shown in FIG. 3. For this reason, 2 lines are delayed afterthe capture of the first data Br is initiated in the blue pixel line 59B(i.e., after the first data Br(B1) corresponding to the first read lineL1 on the original starts to be output) until the capture of the seconddata Gr is initiated in the green pixel line 59G (i.e., until the seconddata Gr(G1) corresponding to the first read line L1 on the originalstarts to be output). Similarly, 2 lines are delayed after the captureof the second data Gr is initiated in the green pixel line 59G (i.e.,after the second data Gr(G1) corresponding to the first read line L1 onthe original starts to be output) until the capture of the third data Rris initiated in the red pixel line 59R (i.e., until the third dataRr(R1) corresponding to the first read line L1 on the original starts tobe output).

Therefore, for example, when the blue pixel line 59B captures the firstdata Br(B6) corresponding to the sixth read line L6, the green pixelline 59G captures the second data Gr(G4) corresponding to the fourthread line L4 on the original, and the output from the red pixel line 59Rrelates to the third data Rr(R2) corresponding to the second read lineL2 on the original.

Now, the process flow in the pre-processing portion 100 will bedescribed.

The first, second, and third data Br, Gr, and Rr (analog signals) thathave been acquired as described above are subjected to the gain andoffset adjustment in the analog processing portion 110, and convertedinto digital signals in the A/D converter 120. The converted digitalsignals are input to the infrared/visible separator 130.

FIG. 14 is a timing chart for describing operations of theinfrared/visible separator 130 in the first reading mode.

The infrared/visible separator 130 receives the first, second, and thirddata Br, Gr, and Rr that have been converted into digital data and theLED on/off switching signal from the LED driver 83. Then, theinfrared/visible separator 130 separates the first data Br into thefirst infrared data IR1(B) and the first visible data VIS1(B), thesecond data Gr into the second infrared data IR2(G) and the secondvisible data VIS2(G), and the third data Rr into the third infrared dataIR3(R) and the third visible data VIS3(R) based on the input LED on/offswitching signal.

This operation will be described in more detail. The infrared/visibleseparator 130 outputs the first, second, and third visible data VIS1(B),VIS2(G), and VIS3(R) based on the first, second, and third data Br, Gr,and Rr obtained from the blue, green, and red pixel lines 59B, 59G, and59R, respectively, while the LED on/off switching signal for turning onthe white LED 92 is output, i.e., while the white LED 92 is turned on.In addition, the infrared/visible separator 130 outputs the first,second, and third infrared data IR1(B), IR2(G), and IR3(R) based on thefirst, second, and third data Br, Gr, and Rr obtained from the blue,green, and red pixel lines 59B, 59G, and 59R, while the LED on/offswitching signal for turning on the infrared LED 93 is output, i.e.,while the infrared LED 93 is turned on.

In the example shown in FIG. 14, as for the first data Br, B1 to B13excluding B6 and B12 are output as the first visible data VIS1(B), andB6 and B12 are output as the first infrared data IR1(B). In addition, asfor the second data Gr, G1 to G11 excluding G4 and G10 are output as thesecond visible data VIS2(G), and G4 and G10 are output as the secondinfrared data IR2(G). Furthermore, as for the third data Rr, R1 to R9excluding R2 and R8 are output as the third visible data VIS3(R), and R2and R8 are output as the third infrared data IR3(R). The first, second,and third infrared data IR1(B), IR2(G), and IR3(R) are output to theinfrared post-processing portion 200. Meanwhile, the first, second, andthird visible data VIS1(B), VIS2(G), and VIS3(R) are output to thevisible post-processing portion 300.

Now, operations of the infrared post-processing portion 200 in the firstreading mode will be described.

Each of the first, second, and third infrared data IR1(B), IR2(G), andIR3(R) input to the infrared shading correction portion 230 of theinfrared post-processing portion 200 is shading-corrected using theinfrared shading data SHD(IR) read from the infrared shading data memory220. By virtue of the infrared shading correction, it is possible tocorrect ununiformity in light intensity distribution of the infrared LED93 for the horizontal scanning direction FS, or ununiformity in outputvalues of each photodiode PD included in the blue, green, and red pixellines 59B, 59G, and 59R for the infrared light. In addition, it ispossible to correct level difference among the first, second, and thirdinfrared data IR1(B), IR2(G) and IR3(R) caused by differenttransmittance in the infrared range. The first, second, and thirdinfrared data IR1(B), IR2(G), and IR3(R) that have beenshading-corrected in an infrared range are output to the rearrangingportion 240.

FIG. 15 is a timing chart for describing operations of the rearrangingportion 240 in the first reading mode.

The rearranging portion 240 receives the first, second, and thirdinfrared data IR1(B), IR2(G), and IR3(R) that have beenshading-corrected in the infrared range. As shown in FIG. 15, althoughthe first, second, and third infrared data IR1(B6), IR2(G4), and IR3(R2)are simultaneously acquired, the third infrared data IR3(R2) is obtainedby reading the second read line L2 on the original, the second infrareddata IR2(G4) is obtained by reading the fourth read line L4 on theoriginal, and the first infrared IR1(B6) is obtained by reading thesixth read line L6 on the original. In addition, although the first,second, and third infrared data IR1(B12), IR2(G10), and IR3(R8) aresimultaneously acquired at the next chance, the third infrared dataIR3(R8) is obtained by reading the eighth read line L8 on the original,the second infrared data IR2(G10) is obtained by reading the tenth readline L10 on the original, and the first infrared data IR1(B12) isobtained by reading the twelfth read line L12 on the original.

In other words, it is recognized that the first, second, and thirdinfrared data IR1(B), IR2(G), and IR3(R) correspond to the output dataobtained by reading even-numbered read lines L2, L4, L6, L8, L10, L12, .. . on the original.

The rearranging portion 240 receives the first, second, and thirdinfrared data IR1(B), IR2(G), and IR3(R), and temporarily buffers them.Then, the rearranging portion 240 rearranges the third, second, andfirst infrared data IR3(R), IR2(G), and IR1(B) in this order and outputsthem as the infrared data IR. As a result, the infrared data IR isoutput in the order of the even-numbered read lines L2, L4, L6, L8, L,L12, . . . . The infrared data IR is output to the identificationinformation analyzing portion 250.

FIG. 16 is a flowchart illustrating a process flow executed in theidentification information analyzing portion 250 in the first readingmode.

When the infrared data IR is input from the rearranging portion 240(step 201), the identification information analyzing portion 250 shapesthe input infrared data IR (step 202). The shaping of the infrared dataIR includes, for example, slanted-angle correction, noise elimination,and the like. In addition, the identification information analyzingportion 250 extracts a bit pattern (e.g., a slanted-line pattern) suchas a slash “/” or a backslash “\” from the shaped infrared data IR (step203). On the other hand, the identification information analyzingportion 250 extracts a synchronization code for determining thetwo-dimensional code position from the shaped infrared data IR (step204). The identification information analyzing portion 250 extracts thetwo-dimensional code with reference to this synchronization codeposition (step 205) and extracts an error correction code (ECC) from thetwo-dimensional code and decodes the ECC (step 206). In addition, theidentification information analyzing portion 250 restores the originalcode information from the decoded information (step 207).

Then, the identification information analyzing portion 250 tries toobtain identification information from the restored code information(step 208). Subsequently, it is determined whether or not theidentification information has been successfully acquired (step 209). Ifit is determined that the identification information has beensuccessfully acquired, the identification information analyzing portion250 outputs the acquired identification information to the datacombining portion 400 (refer to FIG. 5) (step 210). In addition, theidentification information analyzing portion 250 outputs the acquisitioncompletion signal representing that the acquisition of theidentification information has been completed to the reading controller81, the pre-processing portion 100, and the visible post-processingportion 300, and the like (step 211), so that a set of the processes areterminated.

On the other hand, in the step 209, if it is determined that theidentification information cannot be obtained, the process returns tothe step 201, and the identification information analyzing portion 250continues to repeat the same process.

Now, operations of the visible post-processing portion 300 in the firstreading mode will be described.

Each of the first, second, and third visible data VIS1(B), VIS2(G), andVIS3(R) input to the visible shading correction portion 330 of thevisible post-processing portion 300 are shading-corrected using thevisible shading data SHD(VIS) read from the visible shading data memory320. By virtue of the visible shading correction, it is possible tocorrect ununiformity in light intensity distribution of the white LED 92for the horizontal scanning direction FS, or ununiformity in outputvalues of each photodiode PD included in the blue, green, and red pixellines 59B, 59G, and 59R for the white light. The first, second, andthird visible data VIS1(B), VIS2(G), and VIS3(R) that have beenshading-corrected in a visible range are input to the delay processingportion 340.

FIG. 17 is a timing chart for describing operations of the delayprocessing portion 340, the data supplementing portion 350, and theimage processing portion 360 in the first reading mode. Specifically,FIG. 17A illustrates the first, second, and third visible data VIS1(B),VIS2(G), and IVS3(R) input to the delay processing portion 340. Inaddition, FIG. 17B illustrates the first, second, and third visible dataVIS1(B), VIS2(G), and VIS3(R) output from the delay processing portion340. Furthermore, FIG. 17C illustrates image information (includingblue, green, and red data B, G, and R) after the data supplementingprocess by the data supplementing portion 350 and the image processingby the image processing portion 360 have been performed.

The delay processing portion 340 receives the first, second, and thirdvisible data VIS1(B), VIS2(G), and VIS3(R) that have beenshading-corrected in a visible range. As described above, the secondvisible data VIS2(G) is delayed by 2 lines with respect to the firstvisible data VIS1(B), and the third visible data is delayed by 2 lineswith respect to the second visible data VIS2(G).

Therefore, the delay processing portion 340 outputs the third visibledata VIS3(R) without any delay, the first visible data VIS1(B) with adelay amount of 4 lines, and the second visible data VIS2(G) with adelay amount of 2 lines. As a result, the numbers X of the read lines ofthe first, second, and third visible data VIS1(B), VIS2(G), and VIS3(R)are coincident with one another when they are simultaneously output fromthe delay processing portion 340. The first, second, and third visibledata VIS1(B), VIS2(G), and VIS3(R) that have been delayed are input tothe data supplementing portion 350.

In the first, second, and third visible data VIS1(B), VIS2(G), andVIS3(R), the data corresponding to one line is omitted every 5 lines dueto the infrared/visible separation in the aforementionedinfrared/visible separator 130.

Therefore, the data supplementing portion 350 supplements the omitteddata in the first, second, and third visible data VIS1(B), VIS2(G), andVIS3(R) and outputs them. For example, although the data to be insertedbetween VIS1(B5) and VIS1(B7) (shown as dotted lines in the drawing) isomitted in the first visible data VIS1(B), the data supplementingportion 350 supplements VIS1(SB6) in this position. In addition, forexample, although the data to be inserted between VIS2(G3) and VIS2(G5)is omitted in the second visible data VIS2(G), the data supplementingportion 350 supplements VIS2(SG4) in this position. Furthermore, thedata to be inserted between VIS3(R1) and VIS3(R3) and the data VIS3(R7)and VIS3(R9) are omitted in the third visible data VIS3(R), the datasupplementing portion 350 supplements VIS3(SR2) and VIS3(SR8) in thesepositions, respectively.

More specifically, for example, the omitted line may be supplemented byaveraging using the values of 6 pixels (3 leading pixels and 3 trailingpixels) available in 3×3 matrix centering on a target pixel with respectto the omitted line. Otherwise, the omitted line may be simplysupplemented by averaging leading and trailing pixels in a verticalscanning direction. Also, other methods may be used.

The image processing portion 360 performs a predetermined imageprocessing for the first, second, and third visible data VIS1(B),VIS2(G), and VIS3(R) that have been supplemented by the datasupplementing portion 350. In addition, the blue color data B obtainedby processing the first visible data VIS1(B), the green color data Gobtained by processing the second visible data VIS2(G), and the redcolor data R obtained by processing the third visible data VIS3(R) areoutput to the data combining portion 400 (refer to FIG. 5) as imageinformation.

Now, the second reading mode in the step 110 will be described withreference to FIGS. 18 to 20. It should be noted that the second readingmode is executed after the identification information analyzing portion250 of the infrared post-processing portion 200 completes the analysisof the identification information and the acquisition completion signalhas been output while the original is being read in the first readingmode as described above.

FIG. 18 is a timing chart illustrating relationships among the linesynchronization signal Lsync, the LED on/off switching signal, theturning-on/off of the white LED 92 and the infrared LED 93, the CCDcapture signal CCD SH, and the first, second, and third data Br, Gr, andRr in the second reading mode.

In the second reading mode, the CCD driver 82 outputs the LED on/offswitching signal for always turning on the white LED 92 to the LED lightsource 55.

The LED light source 55 always turns on the white LED 92 in response tothis LED on/off switching signal.

In addition, the CCD driver 82 outputs the CCD capture signal CCD SHsynchronized with the line synchronization signal Lsync to the CCD imagesensor 59 (including the blue, green, and red pixel lines 59B, 59G, and59R). The blue, green, and red pixel lines 59B, 59G, and 59Rsequentially output the first, second, and third data Br, Gr, and Rr,respectively, as the read data for one line in a horizontal scanningdirection in response to this CCD capture signal CCD SH.

In this case, the blue, green, and red pixel lines 59B, 59G, and 59R arespaced with an interval of 2 lines in a vertical scanning direction asdescribed above. Therefore, for example, when the blue pixel line 59Bcaptures the first data Br(Bj) corresponding to the jth read line Lj,the green pixel line 59G captures the second data Gr(Gj−2) correspondingto the (j−2)th read line Lj−2, and the red pixel line 59R captures thethird data Rr(Rj−4) corresponding to the (j−4)th read line Lj−4.

FIG. 19 is a timing chart for describing operations of theinfrared/visible separator 130 in the second reading mode.

In the second reading mode, the LED on/off switching signal for alwaysturning on the white LED 92 is output. For this reason, theinfrared/visible separator 130 outputs the first, second, and third dataBr, Gr, and Rr as the first, second, and third visible data VIS1(B),VIS2(G), and VIS3(R) without any change. Therefore, null data arecontinuously output for the first, second, and third infrared dataIR1(B), IR2(G), and IR3(R).

As a result, the infrared post-processing portion 200 stops itsoperation during the second reading mode is executed.

Now, operations of the visible post-processing portion 300 in the secondreading mode will be described.

Each of the first, second, and third visible data VIS1(B), VIS2(G), andVIS3(R) input to the visible shading correction portion 330 of thevisible post-processing portion 300 is shading-corrected using thevisible shading data SHD(VIS) read from the visible shading data memory320. The first, second, and third visible data VIS1(B), VIS2(G), andVIS3(R) that have been shading-corrected in a visible range are input tothe delay processing portion 340.

FIGS. 20A, 20B, and 20C are timing charts for describing operations ofthe delay processing portion 340, the data supplementing portion 350,and the image processing portion 360 in the second reading mode.Specifically, FIG. 20A shows the first, second, and third visible dataVIS1(B), VIS2(G), and VIS3(R) input to the delay processing portion 340.In addition, FIG. 20B shows the first, second, and third visible dataVIS1(B), VIS2(G), and VIS3(R) output from the delay processing portion340. Furthermore, FIG. 20C shows the output image data (including theblue, green, and red color data B, G, and R) output from the imageprocessing portion 360

In the second reading mode, the first, second, and third data Br, Gr,and Rr are respectively input as the first, second, and third visibledata VIS1(B), VIS2(G), and VIS3(R) without separation in theinfrared/visible separator 130 as described above. For this reason, inthe second reading mode, the data supplementing portion 350 does notnecessarily supplement data, and outputs the first, second, and thirdvisible data VIS1(B), VIS2(G), and VIS3(R) input from the delayprocessing portion 340 without any change. In addition, whether or notthe data supplementing should be performed in the data supplementingportion 350 depends on whether or not the acquisition completion signalhas been input from the identification information analyzing portion250. In other words, since some of the first, second, and third visibledata VIS1(B), VIS2(G), and VIS3(R) are omitted due to the separationprocess executed in the infrared/visible separator 130 until theacquisition of the identification information in the identificationinformation analyzing portion 250 is completed, the data issupplemented. On the other hand, after the acquisition of theidentification information is completed, the separation process is notexecuted in the infrared/visible separator 130, and none of the first,second, and third visible data VIS1(B), VIS2(G), and VIS3(R) is omitted.Therefore, the data supplementing is not performed.

Then, a predetermined image processing is performed in the imageprocessing portion 360 for the first, second, and third visible dataVIS1I(B), VIS2(G), and VIS3(R) that have passed through the datasupplementing portion 350. Accordingly, the blue color data B obtainedby performing an image processing for the first visible data VIS1(B),the green color data G obtained by performing an image processing forthe second visible data VIS2(G), and the red color data R obtained byperforming an image processing for the third visible data VIS3(R) areoutput to the data combining portion 400 as image information.

In addition, the identification information input from the infraredpost-processing portion 200 is combined in the data combining portion400 with the blue, green, and red color data B, G, and R correspondingto image information output from the visible post-processing portion300, and then output to devices in the subsequent stage.

FIG. 21 illustrates various image data output in the first reading mode.Specifically, FIGS. 21A, 21B, and 21C illustrate the blue, green, andred color data B, G, and R, respectively, output from the imageprocessing portion 360 of the visible post-processing portion 300. Inaddition, FIG. 21D illustrates the infrared data IR output from therearranging portion 240 of the infrared post-processing portion 200.

For example, in case of the blue color data B shown in FIG. 21A, thedata (B1-B5, B7-B11, B13- . . . in the example shown in the drawing)obtained from the first data Br captured by the blue pixel line 59B whenthe white LED 92 is turned on, and the supplemented data (SB6, SB12, . .. in the example shown in the drawing) obtained from the datasupplementing portion 350 based on the data obtained from the first dataBr are alternately output.

In addition, for example, in case of the green color data G shown inFIG. 21B, the data (G1-G3, G5-G9, G1-G13, . . . in the example shown inthe drawing) obtained from the second data Gr captured by the greencolor pixel line 59G when the white LED 92 is turned on and thesupplemented data (SG4, SG10, . . . in the example shown in the drawing)obtained by the data supplementing portion 350 based on the dataobtained from the second data Gr are alternately output.

Furthermore, for example, in case of the red data R shown in FIG. 21C,the data (R1, R3-R7, R9-R13, . . . in the example shown in the drawing)obtained from the third data Rr captured by the red pixel line 59R whenthe white LED 92 is turned on and the supplemented data (SR2, SR8, . . .in the example shown in the drawing) obtained by the data supplementingportion 350 based on the data obtained from the third data Rr arealternately output.

In other words, in the first reading mode, the data corresponding to 5lines in a vertical scanning direction obtained based on each outputdata from blue, green, and red pixel lines 59B, 59G, and 59R and thesupplemented data corresponding to 1 line in a vertical scanningdirection obtained based on this data are alternately output for theblue, green, and red color data B, G, and R. As a result, the outputdata corresponding to the read line Lx(only L1-L13 are shown in FIG. 21)on the original shown in FIG. 11 are obtained from the blue, green, andred color data B, G, and R.

On the contrary, in case of the infrared data IR shown in FIG. 21D, thedata obtained when the infrared LED 93 is turned on are sequentiallyoutput. Specifically, first of all, the data (R2 in the example shown inthe drawing) obtained from the third data Rr captured by the red pixelline 59R, the data (G4 in the example shown in the drawing) obtainedfrom the second data Gr captured by the green pixel line 59G, and thedata (B6 in the example shown in the drawing) obtained from the firstdata Br captured by the blue pixel line 59B are sequentially output.

Subsequently, the data (R8 in the example shown in the drawing) obtainedfrom the third data Rr captured by the red pixel line 59R, the data (G10in the example shown in the drawing) obtained from the second data Grcaptured by the green pixel line 59G, and the data (B12 in the exampleshown in the drawing) obtained from the first data Br captured by theblue pixel line 59B are sequentially output. Similarly, in thesubsequent stages, the data obtained from the third data Rr captured bythe red pixel line 59R, the data obtained from the second data Grcaptured by the green pixel line 59G, and the data obtained from thefirst data Br captured by the blue pixel line 59B are sequentiallyoutput.

In other words, in case of the infrared data IR in the first readingmode, the data corresponding to one line in a vertical scanningdirection, obtained based on each output data from the red, green, andblue pixel lines 59R, 59G, and 59B, are sequentially output. In thiscase, the output data corresponding to even-numbered read lines L2, L4,L6, L8, L10, L12, . . . of the read lines Lx on the original shown inFIG. 11 are obtained using the infrared data IR. On the contrary, thedata corresponding to the odd-numbered read lines L1, L3, L5, L7, L9,L11, L13, . . . are set to null.

Accordingly, the vertical scanning resolutions of the blue, green, andred color data B, G, and R and the infrared data IR in the first readingmode are set as follows.

Assuming that X denotes the number of lines read by each of the blue,green, and red pixel lines 59B, 59G, and 59R in a vertical scanningdirection of the original, the number of blue read lines correspondingto the first visible data VIS1(B) used to output the blue color data Bis 5X/6. In addition, the number of the green read lines correspondingto the second visible data VIS2(G) used to output the green data G andthe number of red read lines corresponding to the third visible dataVIS3(R) used to output the red color data R are also 5X/6. However,according to the present embodiment, the omitted line having the numberof X/6 is supplemented for the first visible data VIS1(B) when the bluecolor data B is output. Similarly, the omitted lines having the numberof X/6 are supplemented for the second visible data VIS2(G) when thegreen color data G is output and for the third visible data VIS3(R) whenthe red color data R is output. Therefore, the blue, green, and redcolor data B, G, and R are substantially obtained from the number X ofread lines.

On the other hand, assuming that X denotes the number of the lines readin a vertical scanning direction on the original, the number of infraredread lines corresponding to the first infrared data IR1(B) used tooutput the infrared data IR is X/6. In addition, the numbers of theinfrared read lines corresponding to the second infrared data IR2(G)used to output the infrared data IR is X/6 as well as that correspondingto the third infrared data IR3(R) used to output the infrared data IRwhich is also X/6. For this reason, the sum of numbers of the infraredread lines used to output the infrared data IR is X/6+X/6+X/6=X/2.Therefore, the infrared data IR are obtained from a half of the numberof read lines X/2 in comparison with the blue, green, and red color dataB, G, and R.

As described above, in case of the infrared data IR, the number of theread lines becomes a half of the number of the lines substantially readfor the blue, green, and red color data B, G, and R. This means that thevertical scanning resolution for the infrared data IR becomes a half ofthe vertical scanning resolution of the blue, green, and red color dataB, G, and R. Therefore, when the vertical scanning resolution for theblue, green, and red color data B, G, and R is set to 600 spi, thevertical scanning resolution of the infrared data IR becomes 300 spi.

In this case, supposing that the number of pixel lines used to read animage is m, and an interval (gap) between neighboring pixel lines is n,a relationship between a turn-on period T1 of the white LED 92 and aturn-on period T2 of the infrared LED 93 can be expressed as:T1=(m×n−1)×T2  (1).

In the present embodiment, since m is set to 3 and n is set to 2, theturn-on period T1 of the white LED 92 is set to be five times of theturn-on period T2 of the infrared LED 93 as apparent from FIG. 13.However, in the present exemplary embodiment, the first, second, andthird visible data VIS1(B), VIS2(G), and VIS3(R) are respectivelyobtained from the blue, green, and red pixel lines 59B, 59G, and 59R,but the infrared data IR is obtained by summing the data obtained fromthe blue, green, and red pixel lines 59B, 59G, and 59R. Therefore, theratio between both data is not 5:1 but 5:3.

In addition, supposing that the vertical scanning resolution for theblue, green, and red color data B, G, and R (i.e. the vertical scanningresolution of the first data) is called a visible vertical scanningresolution Res(VIS), and the vertical scanning resolution of theinfrared data IR (i.e., the vertical scanning resolution of the seconddata) is called an infrared vertical scanning resolution Res(IR), arelationship between the visible vertical scanning resolution Res(VIS)and the infrared vertical scanning resolution Res(IR) can be expressedas:Res(IR)=Res(VIS)/n  (2).

In the present exemplary embodiment, since n is set to 2, the infraredvertical scanning resolution Res(IR) is a half of the visible verticalscanning resolution Res(VIS). Therefore, when it is desired to make theinfrared vertical scanning resolution Res(IR) and the visible verticalscanning resolution Res(VIS) to have the same level, it is preferable touse a CCD image sensor 59 having a line gap of 1 (i.e., n=1). That is,when a CCD image sensor 59 having a line gap of 3 (i.e., n=3) is used,the resultant infrared vertical scanning resolution Res(IR) becomes ⅓ ofthe visible vertical scanning resolution Res(VIS). The relationshipbetween the visible and infrared vertical scanning resolutions Res(VIS)and Res(IR) may be appropriately set according to the size of the codeimage in the invisible image on the original to be read. In addition,since the horizontal scanning resolution is determined based on anarrangement interval of the photodiodes PD installed in the blue, green,and red pixel lines 59B, 59G, and 59R, the horizontal scanningresolution is constant regardless of whether the visible light or theinfrared light is used.

For example, in the present exemplary embodiment, as shown in FIG. 9,one unit of the two-dimensional code has a size of 0.3 mm×0.3 mm (300μm×300 μm), and a backslash “\” or a slash “/” is formed inside as theinvisible image. In addition, when the invisible image is read, thehorizontal scanning resolution is set to 600 spi, and the infraredvertical scanning resolution Res(IR) is set to 300 spi as describedabove. Since the horizontal scanning resolution is set to 600 spi, thehorizontal scanning length per one sample becomes about 42.3 μm. Inaddition, since the infrared vertical scanning resolution Res(IR) is setto 300 spi, the vertical scanning length per one sample becomes about84.7 μm. Therefore, since one unit of the two-dimensional code is readat least in a size of 6 spots (in a horizontal scanning direction)×3spots (in a vertical scanning direction), the content of the code imageincluded in the invisible image can be sufficiently obtained byperforming the reading in this resolution.

On the other hand, FIG. 22 illustrates various image data output in thesecond reading mode. Specifically, FIGS. 22A, 22B, and 22C show theblue, green, and red color data B, G, and R, respectively, output fromthe image processing portion 360 of the visible post-processing portion300. In addition, since the infrared data IR is not output in the secondreading mode as described above, the infrared data IR is not shown.

For example, in case of the blue color data B shown in FIG. 22A, thedata (Bj to Bj+9, . . . in the example shown in the drawing) obtainedfrom the first data Br captured by the blue pixel line 59B when thewhite LED 92 is turned on are output.

In addition, in case of the green color data G shown in FIG. 22B, thedata (Gj to Gj+9, . . . in the example shown in the drawing) obtainedfrom the second data Gr captured by the green pixel line 59G when thewhite LED 92 is turned on are output.

Furthermore, in case of the red color data R shown in FIG. 22C, the data(Rj to Rj+9, . . . in the example shown in the drawing) obtained fromthe third data Rr captured by the red pixel line 59R when the white LED92 is turned on are output.

That is, in the second reading mode, the data corresponding to each readline in a vertical scanning direction, obtained from on the data outputfrom the blue, green, and red pixel lines 59B, 59G, and 59R, aresequentially output for the blue, green, and red color data B, G, and R.As a result, the output data corresponding to the read lines Lx (only Ljto Lj+9 are shown in FIG. 22) on the original shown in FIG. 11 can beobtained for the blue, green, and red data B, G, and R withoutsupplementing data.

Accordingly, in the second reading mode, the vertical scanningresolution Res(VIS) for the blue, green, and red data B, G, and Rbecomes 600 spi without change.

In the present exemplary embodiment, although the read operation of theoriginal having visible and invisible images has been described, theimage reading apparatus may read the original having only the visibleimage. In this case, an attempt to obtain the identification information(refer to the step 208 of FIG. 16) is continuously performed until theread operation for one page of the original is completed. However, evenif the identification information cannot be obtained, the next operationcan be continued when the read operation for the original is completed(refer to the step 109 of FIG. 10), and any problem does notparticularly occur.

In addition, although the present exemplary embodiment has beendescribed by exemplifying the read operations for the visible andinfrared range images, a plurality of wavelength ranges (including thefirst and second wavelength rages) functioning as a reading target maybe used, and the present invention is not limited thereto.

Furthermore, although the present exemplary embodiment has beendescribed by exemplifying the original-movable reading mode, the presentinvention is not limited thereto, and the present embodiment may besimilarly applied to the original-fixed reading mode.

Second Exemplary Embodiment

The second exemplary embodiment is similar to the first exemplaryembodiment except that a period for generating the line synchronoussignals Lsync, i.e., a line period TL is changed between, when the whiteLED 92 is turned on and when the infrared LED 93 is turned on. Inaddition, in the second exemplary embodiment, like reference numeralswill be used for like elements of the first exemplary embodiment, andtheir detailed descriptions will be omitted.

FIG. 23 is a diagram illustrating an exemplary construction of a VCLKgenerator 86 according to the second exemplary embodiment. The VCLKgenerator 86 includes a first clock generator (a first CLK generator) 86a, a second clock generator (a second CLK generator) 86 b, and a clockselector (a CLK selector) 86 c. The first CLK generator 86 a generates afirst video clock with a predetermined frequency (for example, 60 MHz).In addition, the second CLK generator 86 b generates a second videoclock with a frequency twice the predetermined frequency (for example,120 MHz). Furthermore, the CLK selector 86 c selectively outputs thefirst video clock generated from the first CLK generator 86 a or thesecond video clock generated from the second CLK generator 86 b based onthe LED on/off switching signal input from the LED driver 83.Specifically, the first video clock is output as a video clock when theLED on/off switching signal for turning on the white LED 92 is output,and the second video clock is output as a video clock when the LEDon/off switching signal for turning on the infrared LED 93 is output.

Similarly to the first exemplary embodiment, the line synchronizationsignal generator 87 shown in FIG. 5 is designed to assert the linesynchronization signal Lsync every time the count of the video clockinput from the VCLK generator 86 is coincident with a predeterminedsetup value. Therefore, the line synchronization generator 87 assertsthe line synchronization signal Lsync with a first line period TL1 whilethe first video clock is input. In addition, the line synchronizationsignal generator 87 asserts the line synchronization signal Lsync with asecond line period TL2 which is a half of the first line period TL1while the second video clock is input.

According to the second exemplary embodiment, the sequence of executingthe first reading mode is different from that of the first exemplaryembodiment.

Now, the first reading mode according to the second exemplary embodimentwill be described with reference to FIGS. 24 to 26.

FIG. 24 is a timing chart illustrating relationships among the linesynchronization signal Lsync, the LED on/off switching signal,turning-on/off of the white LED 92 and the infrared LED 93, the CCDcapture signal CCD SH, and the first, second, and third data Br, Gr, andRr in the first reading mode.

When the first reading mode is initiated, the LED driver 83 outputs theLED on/off switching signal based on the line synchronous signal Lsyncinput through the reading controller 81. Specifically, the LED driver 83counts the number of assertions of the line synchronization signalLsync, and outputs to the CLK selector 86 c of the VCLK generator 86 orthe LED light source 55, an LED on/off switching signal for turning ononly the white LED 92 for five lines including the first to fifth countsand turning on only the infrared LED 93 for 2 lines including sixth andseventh counts.

In this case, the CLK selector 86 c of the VCLK generator 86 switchesthe output video signal into the first or second video clock accordingto the LED on/off switching signal input from the LED driver 83.Accordingly, the line synchronization signal generator 87 repeats anoperation of asserting the line synchronization signal Lsync with thefirst line period TL1 while the white LED 92 is turned on and with thesecond line period TL2 while the infrared LED 93 is turned on.

In response to this LED on/off switching signal, the LED light source 55repeats the on/off switching operation for turning on only the white LED92 for five periods (corresponding to five lines) of the first lineperiod TL1 and turning on only the infrared LED 93 for two periods(corresponding to 2 lines) of the next second line period TL2.

Meanwhile, the CCD driver 82 outputs the line synchronization signalLsync synchronized with the CCD capture signal CCD SH to the CCD imagesensor 59 including the blue, green, and red pixel lines 59B, 59G, and59R). In response to this CCD capture signal CCD SH, the blue, green,and red pixel lines 59B, 59G, and 59R sequentially outputs the first,second, and third data Br, Gr, and Rr as the read data for one line in ahorizontal scanning direction.

In this case, similar to the first exemplary embodiment, 2 lines aredelayed for each of the first, second, and third data Br, Gr, and Rroutput from the blue, green, and red pixel lines 59B, 59G, and 59R,respectively. For example, in case of the first data Br, the acquisitionperiod of the first data Br (B6 a, B6 b, B12 a, B12 b, . . . ) obtainedwhen the infrared LED 93 is turned on is a half of the acquisitionperiod of the first data Br(B1˜B5, B7˜B11, B13, . . . ) obtained whenthe white LED 92 is turned on. This also applies to the second and thirddata Gr and Rr.

Now, operations of the infrared/visible separator 130 of thepre-processing portion 100 in the first reading mode will be describedwith reference to the timing chart of FIG. 25.

The infrared/visible separator 130 receives the first, second, and thirddata Br, Gr, and Rr that have been converted into digital signals in theA/D converter 120 and the LED on/off switching signal from the LEDdriver 83. In addition, the infrared/visible separator 130 separates thefirst data Br into the first infrared data IR11(B) and the first visibledata VIS1(B), the second data Gr into the second infrared data IR2(G)and the second visible data VIS2(G), and the third data Rr into thethird infrared data IR3(R) and the third visible data VIS3(R), based onthe input LED on/off switching signal.

In the example shown in FIG. 25, from the first data Br, the data B1 toB13 excluding B6 a, B6 b, B12 a, and B12 b are output as the firstvisible data VIS1(B), and the data B6 a, B6 b, B12 a, and B12 b areoutput as the first infrared data IR1(B). In addition, from the seconddata Gr, the data G1 to G11 excluding G4 a, G4 b, G10 a, and G10 b areoutput as the second visible data VIS2(G), and the data G4 a, G4 b, G10a, and G10 b are output as the second infrared data IR2(G). Furthermore,from the third data Rr, the data R1 to R9 excluding R2 a, R2 b, R8 a,and R8 b are output as the third visible data VIS3(R), and the data R2a, R2 b, R8 a, and R8 b are output as the third infrared data IR3(R),respectively. These first, second, and third infrared data IR1(B),IR2(G), and IR3(R) are output to the infrared post-processing portion200. On the other hand, the first, second, and third visible dataVIS1(B), VIS2(G), and VIS3(R) are output to the visible post-processingportion 300. Subsequently, similar to the first exemplary embodiment,the blue, green, and red color data B, G, and R are output after thedata supplementing process is performed.

Now, operations of the rearranging portion 240 of the infraredpost-processing portion 200 in the first reading mode will be describedwith reference to the timing chart illustrated in FIG. 26.

The rearranging portion 240 receives the first, second, and thirdinfrared data IR1(B), IR2(G), and IR3(R) that have beenshading-corrected in an infrared range by the infrared shadingcorrection portion 230. As shown in FIG. 26, for the first, second, andthird infrared data IR1(B6 a), IR2(G4 a), and IR3(R2 a) that aresimultaneously acquired, the third infrared data IR3(R2 a) is obtainedby reading the upstream side L2 a of the second read line L2, the secondinfrared data IR2(G4 a) is obtained by reading the upstream side L4 a ofthe fourth read line L4, and the first infrared data IR1(B6 a) isobtained by reading the upstream side L6 a of the sixth read line L6,respectively. In addition, for the first, second, and third infrareddata IR11(B6 b), IR2(G4 b), and IR3(R2 b) that are simultaneouslyobtained at the next time, the third infrared data IR3(R2 b) is obtainedby reading the downstream side L2 b of the second read line L2, thesecond infrared data R2(G4 b) is obtained by reading the downstream sideL4 b of the fourth read line L4, and the first infrared data IR1(B6 b)is obtained by reading the downstream side L6 b of the sixth read lineL6, respectively.

Furthermore, for the first, second, and third infrared data IR1(B12 a),IR2(G10 a), and IR3(R8 a) that are simultaneously obtained at the nexttime, the third infrared data IR3(R8 a) is obtained by reading theupstream side of the eighth read line L8, the second infrared dataIR2(G10 a) is obtained by reading the upstream side of the tenth readline L10, and the first infrared data IR1(Bl2 a) is obtained by readingthe upstream side of the twelfth read line L12, respectively. Then, forthe first, second, and third infrared data IR1(B12 b), IR2(G10 b), andIR3(R8 b) that are simultaneously obtained at the next time, the thirdinfrared data IR3(R8 b) is obtained by reading the downstream side ofthe eighth read line L8, the second infrared data IR2(G10 b) is obtainedby reading the downstream side of the tenth read line L10, and the firstinfrared data IR1(B12 b) is obtained by reading the downstream side ofthe twelfth read line L12, respectively.

That is, according to the second exemplary embodiment, it is recognizedthat the first, second, and third infrared data IR1(B), IR2(G), andIR3(R) correspond to the output data read by dividing each of theeven-numbered read lines L2, L4, L6, L8, L10, L12, . . . on the originalinto 2 lines in a vertical scanning direction.

The rearranging portion 240 receives and temporarily buffers the first,second, and third infrared data IR1(B), IR2(G), and IR3(R). In addition,the rearranging portion 240 rearranges the third, second, and firstinfrared data IR3(R), IR2(G), and IR1(B) in this order and outputs themas the infrared data IR. As a result, for the infrared data IR, the dataare output in the order of L2 a, L2 b, L4 a, L4 b, L6 a, L6 b, L8 a, L8b, L10 a, L10 b, L12 a, L12 b . . . obtained by dividing each of theeven-numbered read lines into 2 lines in a vertical scanning direction.The infrared data IR is output to the identification informationanalyzing portion 250, and the identification information is analyzedusing the process similar to the first exemplary embodiment.

As described above, according to the second exemplary embodiment, thesecond line period TL2 when the infrared LED is turned on (i.e., whenthe first, second, and third infrared data IR1(B), IR2(G), and IR3(R)are acquired) is set to a half of the first line period TL1 when thewhite LED 92 is turned on (i.e., when the first, second, and thirdvisible data VIS1(B), VIS2(G), and VIS3(R) are acquired). As a result,it is possible to obtain the infrared data IR by dividing each of theeven-numbered read lines into 2 lines. Therefore, it is possible tomatch the vertical scanning resolution Res(IR) of the infrared data IRwith the vertical scanning resolution Res(VIS) of the visible data inappearance.

The foregoing description of the exemplary embodiments of the presentinvention has been provided for the purposes of illustration anddescription. It is not intended to be exhaustive or to limit theinvention to the precise forms disclosed. Obviously, many modificationsand variations will be apparent to practitioners skilled in the art. Theembodiments were chosen and described in order to best explain theprinciples of the invention and its practical applications, therebyenabling others skilled in the art to understand the invention forvarious embodiments and with the various modifications as are suited tothe particular use contemplated. It is intended that the scope of theinvention be defined by the following claims and their equivalents.

1. An image reading apparatus comprising: a light source having a firstluminescent portion that outputs a light with a first wavelength rangeand a second luminescent portion that outputs a light with a secondwavelength range, the first wavelength range being different from thesecond wavelength range; a light-receiving portion that receives areflection light reflected from an original irradiated by the lightsource; a scanning portion that shifts a reading position of theoriginal read by the light-receiving portion in a vertical scanningdirection, by changing a relative position between the original and thelight-receiving portion; a switching portion that alternately turns onthe first and second luminescent portions when the scanning portionshifts the reading position; a separation portion that separates datareceived by the light-receiving portion into a first data obtained whenthe first luminescent portion is turned on and a second data obtainedwhen the second luminescent portion is turned on; an image informationacquisition portion that acquires an image information based on thefirst data separated by the separation portion; and an identificationinformation acquisition portion that acquires an identificationinformation based on the second data separated by the separationportion.
 2. The image reading apparatus of claim 1, wherein the firstluminescent portion outputs a white light as the light with the firstwavelength range, and the second luminescent portion outputs an infraredwavelength range light as the light with the second wavelength range. 3.The image reading apparatus of claim 1, wherein the switching portionturns on only the first luminescent portion after the identificationinformation acquisition portion acquires the identification information.4. The image reading apparatus of claim 1, wherein the image informationacquisition portion supplements a data omitted in the first data thatresults from when the image information is acquired when the secondluminescent portion is turned on.
 5. The image reading apparatus ofclaim 4, wherein the image information acquisition portion stopssupplementing the data omitted after the identification informationacquisition portion acquires the identification information.
 6. Theimage reading apparatus of claim 1, wherein the image informationacquisition portion comprises a first shading correction portion thatcorrects a luminescent characteristic of the first luminescent portionand that corrects a light-receiving characteristic of thelight-receiving portion, and the identification information acquisitionportion comprises a second shading correction portion that corrects aluminescent characteristic of the second luminescent portion and thatcorrects a light-receiving characteristic of the light-receivingportion.
 7. The image reading apparatus of claim 1, wherein thelight-receiving portion comprises a plurality of pixel lines that extendalong a horizontal scanning direction that are arranged in order along avertical scanning direction that is orthogonal to the horizontalscanning direction, the separation portion separates a plurality of datareceived by the plurality of pixel lines into a plurality of first dataand a plurality of second data, the image information acquisitionportion acquires an image information by processing each data of theplurality of first data, and the identification information acquisitionportion acquires an identification information by processing a thirddata obtained by arranging a plurality of second data.